Cuscuses.1 The dental formula is I -f- C -J- Pm f- M -|; the last
premolar is a great blade-shaped tooth like that of Potorous.
jtfbtotherium was a creature smaller than Diprotodon, but still
of large size; it is helieved to have been a burrowing creature,
and to connect the Wombats with Diprotodon. More certainly
allied to the existing Wombat was Pfoascolonus, a Wombat as
big as a Tapir.
Of extinct American Diprotodonts the Epanorthidae, already
referred to in connexion with the living Caemolestes, were the most
prominent forms. The genus EpanortTius occurs in the Santa Cruz
formation of Patagonia, which is believed to be Miocene. The
incisors are three in the upper jaw ; and the single incisor of each
ramus of the lower jaw is a great chisel-shaped, cutting instrument.
Alderites is also typically Biprotodont by reason of the large
projecting incisors of the lower jaw. It has a large cutting
tooth in the lower jaw, which appears to be the last premolar,
and is thus comparable to the vgreat cutting tooth of the lower
jaw aud of the upper jaw of the extinct Fhalanger, Thylacoleo.
,* Quite recently (Proc. Linn, Soc. NmS. W. 1898, p. 1) the carnivorous character
of Tkylaeoileo lias been reasserted "by Mr. Broom.